Add configurability of delete timeout

Previously the timeout for deleting chart releases was 300s and
not configurable, this patchset makes it so via a new
`delete.timeout` property in the `armada/Chart/v1` schema.

Helm releases deleted which do not correspond to documents in this
schema still do not use a configurable timeout. Those will be
considered separately.

This also includes a minor logging fix.

Change-Id: Ia588faaafd18a3ac00eed3cda2f0556ffcec82c9

armada/tests/unit/handlers/test_armada.py

@@ -412,7 +412,10 @@ class ArmadaHandlerTestCase(base.ArmadaTestCase):
                             protected = chart.get('protected', {})
                             if not protected:
                                 expected_uninstall_release_calls.append(
-                                    mock.call(release_name))
+                                    mock.call(
+                                        release_name,
+                                        purge=True,
+                                        timeout=const.DEFAULT_DELETE_TIMEOUT))
                                 expected_install_release_calls.append(
                                     mock.call(
                                         mock_chartbuilder().get_helm_chart(),